Process for the treatment of substrate-variable methane emissions

ABSTRACT

The invention relates generally to a system and method the treatment of substrate-variable gaseous emissions comprising dynamic concentrations of organic materials comprising methane and one or more non-methane organic compounds that can be metabolized by methane-oxidizing microorganisms, and in one specific embodiment, to a system and method for the treatment of substrate-variable methane emissions through the use of methanotrophic microorganisms in a species-universal polymer production process. Certain embodiments of the invention are particularly advantageous because they reduce environmentally-destructive methane emissions and produce harvestable end-products.

RELATED APPLICATIONS

This application is the U.S. National Phase application under 35 U.S.C.§371 of International Application PCT/US2005/047415 filed Dec. 29, 2005,(published as WO 2007/024255), which claims the benefit of ProvisionalApplication No. 60/721,938, filed Sep. 29, 2005, and is acontinuation-in-part of co-pending patent application Ser. No.11/208,808, filed Aug. 22, 2005, which claims the benefit of ProvisionalApplication No. 60/603,857, filed Aug. 24, 2004; wherein patentapplication Ser. No. 11/208,808 is a continuation-in-part of co-pendingpatent application Ser. No. 10/687,272, filed Oct. 15, 2003, now issuedas U.S. Pat. No. 6,982,161; and wherein the disclosures of all of theseapplications are incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates generally to a system and method for thetreatment of methane emissions, and in one specific embodiment, to asystem and method for the treatment of methane emissions through the useof methanotrophic microorganisms.

2. Description of the Related Art

Methane emissions, or methane off-gases, are generated by a variety ofnatural and human-influenced processes, including anaerobicdecomposition in solid waste landfills, enteric fermentation in ruminantanimals, organic solids decomposition in digesters and wastewatertreatment operations, and methane leakage in fossil fuel recovery,transport, and processing systems. As a particularly potent greenhousegas, methane emissions are responsible for about twenty percent ofplanetary warming, and thus represent a significant environmentalconcern. Accordingly, there have been numerous efforts in the past toremediate, control, and/or otherwise treat methane emissions.

In addition to processing methane that is emitted from landfills, coalmines, wastewater treatment plants, manure digesters, agriculturaldigesters, compost heaps, enclosed agricultural feedlots, leaking orotherwise emitting petroleum systems, several embodiments of the presentinvention are directed to capturing and processing methane emitted byruminant animals. Methane emissions from ruminant animals account forabout twenty percent of total global methane emissions, and atmosphericmethane accounts for about twenty percent of planetary warming. Inaddition to the environmentally destructive effects of ruminant animalmethane emissions, such emissions represent wasted energy, as asignificant percentage of the food ruminant animals eat is lost asmethane. Accordingly, there have been significant efforts in the past toreduce ruminant animal methane emissions.

Ruminant animal methane emissions, or, more specifically, entericfermentation methane emissions, originate in the four-stomach digestivetract common to all ruminant animals, which includes the rumen, a largeforestomach connected to the four-stomach digestive tract. The rumencontains a host of digestive enzymes, fungi, bacterium, and protozoa,and the bulk of digestion, as well as methane production via entericfermentation, takes place here. Not surprisingly, all prior efforts toreduce enteric fermentation methane emissions from ruminant animals,which include dairy cows, beef cattle, sheep, goats, water buffalo, andcamels, have focused on modifications associated with the rumen ordigestive tract.

Several methods are known for the treatment of natural andhuman-influenced methane emissions Used in conjunction with well-knownmethane emissions collection methods, such as landfill gas extractionwells/blowers and coal mine methane ventilation systems, the treatmentof air containing captured methane emissions includes the use ofturbines, microturbines, engines, reverse-flow reactors, fuel cells, andboilers to convert methane emissions into heat and/or electricity. Otherwell-known methods for the treatment of methane emissions include theconversion of methane emissions into pipeline-quality, liquefied, orcompressed natural gas.

The treatment and utilization of methane off-gases for the production offuel, heat, and/or electricity is described by a number of patents,including U.S. Pat. Nos. 5,642,630, 5,727,903, 5,842,357, 6,205,704,6,446,385, and 6,666,027, herein incorporated by reference. U.S. Pat.No. 5,642,630 describes the use of landfill gas to produce high qualityliquefied natural gas, liquefied carbon dioxide, and compressed naturalgas products. U.S. Pat. No. 5,727,903 describes the use of landfill gasto create vehicle grade fuel. U.S. Pat. No. 5,842,357 describes the useof landfill gas to create high grade fuel and food-grade carbon dioxide.U.S. Pat. Nos. 6,205,704 and 6,446,385 describe the use of landfill gasto provide heat, electricity, and/or carbon dioxide to enhancegreenhouse operations. U.S. Pat. No. 6,666,027 describes the use ofoff-gas from landfills and digesters to power turbines for electricitygeneration.

Although each of these methods is effective at treating methaneemissions under a specific range of conditions, none are known to beeconomically and/or technologically feasible under a range ofsub-optimal methane-in-air conditions, including conditions where theflow rate, concentration, or purity of methane gas emissions isvariable, unpredictable, low, and/or otherwise unfavorable.

Methane-utilizing, or methanotrophic, microorganisms are well-known inthe microbiology art for their capacity to grow and reproduce usingmethane as a source of carbon and/or energy, particularly in a widerange of diverse methane availability conditions. Accordingly,methanotrophic microorganisms have been proposed in the past as apotential tool for the remediation of methane emissions, particularly inconditions where other treatment methods are technologically and/oreconomically unfeasible.

Two methods have been proposed for the utilization of methanotrophicmicroorganisms to treat methane emissions. In one proposed process,methanotrophic microorganisms are naturally present or purposefullysituated in high-methane emissions environments, such as landfill coversor coal mines, are provided with growth-stimulating nutrients, such asoxygen, water, or mineral salts, to encourage increased microbialmethane emission uptake rates. This method may be carried out usingnutrient injection methods such as air or water sparging to induceincreased methanotrophic growth and oxidation rates in high emissionsenvironments. U.S. Pat. No. 6,749,368, for example, describesmethanotrophic microorganisms that are placed in an aerated soil coverabove a municipal landfill in order to oxidize and reduce methaneemissions.

In a second proposed process, air containing methane emissions isdiverted into an environment containing methanotrophic microorganisms inorder to cause the microbial breakdown of methane emissions. This methodmay be carried out by diverting air containing methane emissions into abiofiltration column containing methanotrophic microorganisms, water,and a microorganism growth medium, whereby electricity, water, nitrogen,trace minerals, and other materials are continuously added to andconsumed by the system in order to effect the microbial breakdown ofmethane emissions.

Both of these prior methanotrophic treatment techniques cannoteffectively or efficiently reduce methane emissions. Indeed, theapplication of these processes has been precluded in practice becausewhile both generate continuous and costly requirements forsupply-limited materials, such as electricity and minerals, neithergenerates direct economic benefits to recover the capital costs oftreatment, and the use of methanotrophic microorganisms for thetreatment of methane emissions is simply too costly to operate andsustain over time. Prior to the applicants' discovery, no methods wereknown to enable the practical sustainability of the biological treatmentof methane emissions, and, accordingly, the utilization ofmethanotrophic microorganisms for the treatment of methane emissions hasbeen precluded in practice.

Accordingly, there exists a significant need to develop a system thatenables methanotrophic methane emissions treatment to betechnologically, financially, and logistically sustainable and, thus,viable in practice

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention address the need for asystem that enables methane emissions treatment to be technologically,financially, and logistically sustainable and viable. Prior toapplicants' invention, gaseous emissions comprising methane have neverbeen used in conjunction with methanotrophic microorganisms toeffectively reduce the amount of environmentally destructive methanepollution and to create a harvestable product from that methane.

In one preferred embodiment, the gaseous emissions (which comprise someamount of methane) from landfills, coal mines, agricultural sites, orpetroleum sites are captured and conveyed to a bioreactor containingmethanotrophic microorganisms. The gaseous emissions do not need toundergo substantial purification. The microorganisms use the methane asa source of carbon or energy, and, in some embodiments produce usefulend-products such as polymers. The polymers can then be used tosynthesize various types of biodegradable materials. For example, thepolymers can be used to produce plastics because, in some cases, thephysical properties of the polymers produced by the methanotrophicmicroorganisms are very similar to those of polypropylene. However, thepolymers produced by the methanotrophic microorganisms arebiodegradable, and therefore environmentally friendly. Thus, somepreferred embodiments of the invention offer a tremendous benefit to theenvironment in at least two ways: first, methane emissions aresubstantially reduced on the front end, and second, a biodegradablepolymer is produced in useful quantities as the end-product.

The term “gaseous emission” as used herein shall mean off-gases and/orgases emitted by natural and/or human-influenced processes, includinganaerobic decomposition in solid waste landfills, enteric fermentationin ruminant animals, organic decomposition in digesters and wastewatertreatment operations, agricultural sites, and in fossil fuel recovery,transport, and processing systems.

Although the prior art recognized that methanotrophic organisms coulduse methane to produce polymers, the prior art did not teach or suggestan effective method by which destructive gaseous emissions that comprisemethane could be used to produce polymers. Thus, prior to applicants'invention, the production of useful quantities of polymers bymethanotrophic organisms was not feasible, because the process, which(among other drawbacks) required a pure and/or concentrated source ofmethane, could only be done on a small scale. Moreover, because a pureand/or concentrated source of methane was required, the costs ofoperating the system was extremely high. Preferred embodiments of thepresent invention, however, do not require an artificial laboratorygrade methane as the primary source of carbon or energy for themethanotrophic organisms. Instead, environmentally destructive gasesthat are already present in the environment can be used as the source ofmethane.

Moreover, preferred embodiments of the present invention areparticularly advantageous because they can use gaseous emissionscomprising low concentrations of methane, rather than pure methane.Although certain turbine systems can convert gaseous emissions intoenergy, the concentration of methane must be high. Although certain fuelcells can use methane in low concentrations, gaseous emissions cannot beused (the methane must be substantially pure). In one preferredembodiment of the current invention, gaseous emissions comprisingmethane in a concentration of less than about 40%, less than about 30%,less than about 20%, less than about 10%, less than about 5%, and lessthan about 1% can be used. Thus, several embodiments of the presentinvention are particularly useful for older landfills, which may producemethane in concentrations of about 0.1% to less than about 20% of totalgaseous emissions as they age. Likewise, several embodiments of thepresent invention are particularly useful for coal mines, which mayproduce methane in concentrations of less than about 5% of total gaseousemissions, and in some cases about 1% methane. Thus, without the benefitof certain preferred embodiments of applicants' invention, thesepolluting systems—which alone produce methane as a small part of theirtotal gaseous emissions—cumulatively contribute significantly to thetotal amount of methane in the environment and thus ultimately to thegreenhouse effect.

In one embodiment of the invention, the system comprises means to enablethe practical application of methanotrophic microorganisms to methaneemissions treatment, particularly in a manner that does not rely on areduction in the operating costs of treatment. In other words, in oneembodiment, methanotrophic microorganisms can be used to reduce methanepollutants in the environment without relying on altering themethanotrophic microorganisms (e.g., by genetic engineering, etc.). Inone embodiment, naturally occurring methanotrophic microorganisms areused to reduce the methane concentration of gaseous emissions.

As discussed previously, methane is an environmentally-destructivematerial and previously unusable source of energy, which, according toone preferred embodiment of the invention, is used to produce a usefulend-product that can be used or sold for use, providing an economicincentive to a methane emissions reduction effort. Although in oneembodiment, the harvestable useful end-product is a polymer, anotherharvestable good is the microorganism culture itself. Thus, in anotherembodiment, gaseous emissions comprising methane are used to grow amicroorganism culture to a density that is capable of being harvestedand commercially traded. In sufficient quantities, the microorganismculture can be used, for example, as a nutrition source for livestock.In one embodiment, the end-product is a culture of microorganisms, orthe products generated by those microorganisms.

In one embodiment of the invention, methane emissions are processed toproduce useful and harvestable products. These products include, but arenot limited to: protein-rich biomass, polyhydroxyalkanoate (PHA),polyhydroxybutyrate (PHB), polyhydroxybutyrate-valerate (PHB/V),particulate or soluble methane monooxygenase (pMMO or sMMO,respectively), vaccine derivatives, enzymes, polymers, cellularmaterials, formaldehyde, and methanol, or a combination thereof. In thecommercial and industrial biotechnology art, methanotrophicmicroorganisms can be manipulated and processed according to severalembodiments of the present invention to generate useful, defined, andharvestable goods in sterile, semi-sterile, and non-sterile conditions.

In one embodiment of the invention, a culture of suitable microorganismsis provided for the efficient and effective treatment of methaneemissions. The prior art generally criticizes the use of methanotrophicorganisms to treat methane emissions, primarily because such a processwas thought to be unpredictable, inefficient, and unreliable. Forexample, the prior art teaches that bioremediation and biofiltrationgenerates a microorganism conglomerate that is non-specific,non-defined, and/or highly variable according to shifts in nutrientavailability, air contamination, species interaction, and so on. Asemphasized in U.S. Pat. No. 6,599,423, “prior art teaches that ex situbiofilters and bioreactors are akin to microorganism zoos, with themicroorganism cultures naturally adapting, dominating, and maintainingthemselves according the various compounds, food sources, andcontaminants present or fed to the biodegradation media . . . changes,adaptations, and dominance of certain cultures will occur even in suchisolated and inoculated cultures after operation begins and thebiofilters or bioreactors are subjected to complex mixtures of foodsources, contaminants, and microorganisms present in the naturalenvironment.” Microbial cultures and the byproducts generated from thegrowth thereof may be incidentally created in the course ofbioremediation, as in the course of any microorganism growth, but,according to the prior art, only in a variable, non-specific, diffuse,unpredictable, speculative, or otherwise non-useful manner. By contrast,in a preferred embodiment of the present invention, a system of usingmicroorganisms in a highly controlled manner for the treatment ofgaseous emissions is provided.

The viability and utility of methanotrophic emissions treatment may beaugmented by increasing the growth or emissions oxidation rate ofmethanotrophic microorganisms in order to reduce the capital andoperating costs of treatment. While this optimization method rendersmethanotrophic treatment more efficient, it does not overcome thechallenge associated with the continuous generation of non-recoverablecosts, and no methods are known in the prior art to optimize themethanotrophic bioremediation process in such a way as to enablepractical sustainability. Prior to the applicants' invention, the onlymethods available for treating methane emissions involved environmentaldegradation and wasted energy associated with the venting, compression,conversion, and/or combustion of methane emissions.

Prior to the applicants' discovery, it was not recognized thatcommercial, academic, and/or industrial growth and processing methodsknown to enable the microbial creation of harvestable products could beapplied to overcome previously impassable and fundamental treatmentchallenges in the field of methane emissions treatment. In particular,it was not known that the use of methanotrophic processes able toengender defined and harvestable bio-based goods, specifically insterile, semi-sterile, and non-sterile conditions, could be used as anovel methane emissions treatment method to overcome previouslyimpassable practical viability and sustainability challenges. Thus,according to a preferred embodiment of the present invention, a methodis provided to enable the practical viability of the biologicaltreatment and utilization of methane emissions. In one embodiment, themethod enables the utilization of methane emissions through theproduction of harvestable goods.

In a preferred embodiment of the invention, an apparatus or system forprocessing methane emissions and producing harvestable products isprovided. In one embodiment, the system comprises (i) a source ofgaseous emissions, wherein the gaseous emissions comprise methane and atleast one non-methane compound, (ii) methanotrophic microorganisms thatuse methane as a source of carbon or energy, (iii) a bioreactor thatencloses or contains the methanotrophic microorganisms, and (iv) aconveyer that conveys the gaseous emissions into the bioreactor, therebyexposing the methanotrophic microorganisms to the gaseous emissions andcausing the methanotrophic microorganisms to produce a harvestableproduct after using the methane as a source of carbon or energy.

In accordance with one embodiment of the invention, a novel method forenabling the viable treatment of air containing methane emissions isprovided. In one embodiment, methanotrophic microorganisms and aircontaining methane emissions are mutually-exposed to cause or enableharvestable product formation. The harvestable product may be used orsold. In another embodiment of the invention, air containing methaneemissions may be used to create single cell protein, enzymes, polymers,or other bio-based products in a manner that enables product harvest.

In one embodiment, the invention comprises a method of processingmethane emissions for the production of a harvestable product,comprising: providing a gaseous emission comprising methane andmethanotrophic microorganisms, exposing the methanotrophicmicroorganisms to the gaseous emission, wherein the methanotrophicmicroorganisms use at least a portion of the methane as a source ofcarbon or energy, and wherein the methanotrophic microorganisms producea harvestable product after using the methane as a source of carbon orenergy.

In one embodiment, the harvestable product comprises a polymer (such aspolyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), andpolyhydroxybutyrate-valerate (PHB/V)). In another embodiment, theharvestable product comprises one or more of the following:microorganism biomass, methane monooxygenase, protein-rich biomass,enzymes, and cellular contents. In yet another embodiment, theharvestable product comprises a quantifiable reduction in methaneemissions.

In several embodiments, the gaseous emission comprises a gas selectedfrom the group consisting of one or more of the following: carbondioxide, ammonia, nitrous oxide, and ozone. In one embodiment, thegaseous emission comprises unpurified landfill gas or partially purifiedlandfill gas. In one embodiment, one or more impurities are removed fromthe gaseous emission. In another embodiment, the gaseous emission isdisinfected using ultraviolet light.

In one embodiment, the invention comprises harvesting the harvestableproduct for commercial or industrial sale or use.

In one embodiment, the invention comprises substantially reducing oreliminating the concentration of nitrogen available to themethanotrophic microorganisms.

In one embodiment, the invention comprises using gaseous emissionshaving methane concentrations in the range of about 0.1% to about 10%,in the range of about 10% to about 20%, and at concentrations greaterthan about 20%. In another embodiment, the methane concentration is lessthan about 5%. In yet another embodiment, the methane concentration isbetween about 30% to about 60% of the total gaseous emissions, andcarbon dioxide concentration is about 30% to about 60%. The latternumbers are typical of certain landfill emissions.

In one embodiment, the gaseous emission is generated by one or more ofthe following: coal mine, wastewater treatment operation, agriculturaldigester, enclosed feedlot, petroleum transport system, and petroleumrecovery system. In another embodiment, the gaseous emission isgenerated by one or more ruminant animals.

In one embodiment, the microorganisms comprise naturally-occurring orgenetically-modified microorganisms, or a combination thereof, that usemethane as a source of carbon or energy for growth or reproduction. Themethanotrophic microorganisms may include one or more of the following:Methylococcus capsulatus, Alcaligenes acidovorans, Bacillus firmus, andBacillus brevis.

In a further embodiment, the gaseous emission comprises a non-methanecompound, wherein the non-methane compound is an organic compound. Inanother embodiment, the gaseous emission comprises a non-methanecompound such as toluene, benzene, methanol, propylene, alkenes,alcohol, ether, and trichloroethylene, or a combination thereof.Non-methane compounds may also include non-methane gases such as carbondioxide, ammonia, nitrous oxide, and ozone.

In one embodiment, the non-methane compound is metabolized, consumed, orused by the methanotrophic microorganisms.

In yet another embodiment, the invention comprises reducing theconcentration of methane to a concentration compliant with applicableenvironmental regulations or laws. In the United States, for example,preferred embodiments of the invention reduce methane to concentrationssuggested or mandated by local, state, and federal EPA guidelines.

In one embodiment, the present invention comprises a method of producinga biodegradable polymer from landfill gas. In one embodiment, the methodcomprises obtaining landfill gas, wherein the landfill gas comprisesmethane, enclosing the landfill gas in a bioreactor containingmethanotrophic microorganisms and growth medium, and inducing themethanotrophic microorganisms to produce biodegradable polymer bysubstantially reducing or depleting the growth medium of any nitrogen.In one embodiment, the method further comprises harvesting thebiodegradable polymer.

In one embodiment of the present invention, a system to reduce methaneemissions or gaseous emissions comprising methane is provided. In oneembodiment, the emissions are produced by land fills, waste processingsites, coal mines, and other similar systems created by humans. Inanother embodiment, the emissions are produced by ruminant animals.

Thus, in accordance with several embodiments, methane produced throughruminant animal enteric fermentation is used as a source of carbonand/or energy for the induction of a methane-driven process and/or forthe production of methane-derived materials, such as methane-utilizingmicroorganisms, heat, and/or electricity.

In one preferred embodiment, the present invention comprises a system orapparatus for processing methane emissions produced by one or moreruminant animals. In one embodiment, the system comprises (i) one ormore ruminant animals that emit gaseous emissions through entericfermentation, wherein the gaseous emissions comprise methane and atleast one non-methane compound, (ii) an enclosure for enclosing theruminant animals, (iii) a methane-consumption means that uses methanefor the production of a product, and (iv) a conveyer that conveys thegaseous emissions to the methane-consumption means, wherein themethane-consumption means is exposed to the methane in the gaseousemissions and uses the methane to generate a harvestable product.

In one embodiment, the present invention comprises a method forprocessing methane emissions produced by one or more ruminant animalscomprising providing one or more ruminant animals that emit gaseousemissions through enteric fermentation. The gaseous emissions comprisemethane, airborne materials, and at least one other gas. The methodfurther comprises enclosing the ruminant animals in an enclosure,thereby at least partially enclosing the gaseous emissions. The methodalso comprises providing a methane-consumption means, or methaneconsumer, that uses methane to produce a product, and conveying thegaseous emissions to the methane-consumption means. In one embodiment,the method includes causing the methane-consumption means to process themethane to generate a product. The term “causing” is a broad term andincludes the act of simply causing methane to come into contact with themethane consumer, and letting nature take its course. In embodimentswhere engines, turbines or fuel cells are used, the act of causingincludes supplying energy to the various components.

In one embodiment, this process of treating gaseous emissions emitted byruminant animals comprises a) enclosing one or more ruminant animals inan enclosure means, such as a barn, and b) contacting air contained insuch an enclosure means, including the enteric fermentation methanecontained therein, with a methane-consumption system, whereby entericfermentation methane emissions are utilized as a novel source of carbonand/or energy for the induction of a methane-based process and/or forthe production of methane-based products, such as heat, electricity,and/or methane-utilizing microorganisms.

In a further embodiment, the method of treating ruminant emissionscomprises: (a) providing one or more ruminant animals, (b) providingenteric fermentation-derived methane gas that has been emitted by theanimals, including air containing the methane, (c) providing means tocapture, consolidate, and/or direct the methane, including providing anenclosure means to enclose the animals, the air, and the methane andproviding an air conveyor to direct the air and the methane, (d)providing a methane-consumption means which can use the methane as asource of carbon and/or energy in a methane-based process and/or for theproduction of methane-based goods, and (e) contacting the methane withthe methane-consumption means to cause the methane-consumption means tooxidize, consume, and/or otherwise utilize the methane for the operationof a methane-based process or for the production of one or moremethane-based products, including methane-utilizing microorganisms,heat, and/or electricity.

In another embodiment, this method comprises: (a) providing one or moreruminant animals, (b) providing an enclosure means to fully or partiallyenclose and/or otherwise encapsulate the animals, (c) providing entericfermentation-derived methane gas that has been emitted by the animals,(d) providing enclosure air that has been combined with the methane inthe enclosure means, (e) providing a methane-consumption means which canuse the methane as a source of carbon and/or energy for the induction ofa methane-based process or the production of methane-based goods, (f)providing a means for contacting the air containing the methane with themethane-consumption means, including a means for the conveying the airto the methane-consumption means whereby the methane can be utilized asa source of carbon and/or energy by the methane-consumption means, (g)mutually-contacting and/or exposing the methane and themethane-consumption means to cause the methane-consumption means tooxidize, consume, and/or otherwise utilize the methane for the inductionof one or more methane-based processes or for the production of one ormore methane-based products, including methane-utilizing microorganisms,heat, and/or electricity, whereby the methane produced by the animals isutilized for the sustained production of the process and/or the productsin a specified apparatus.

As discussed previously, methane is an environmentally-destructivematerial and previously unusable source of energy, which, according toone preferred embodiment of the invention, is used to produce a usefulend-product that can be used or sold for use, providing an economicincentive to a ruminant animal methane emissions reduction effort. Inone embodiment, the end-product is heat. In another embodiment, theend-product is fuel. In yet another embodiment, the end-product iselectricity. In yet another embodiment, the end-product is another formof energy. In a further embodiment, the end-product is the culture ofmicroorganisms.

In one embodiment using ruminant animal emissions, the enclosure means,or enclosure, includes any means by which the animals are fully orpartially enclosed or encapsulated. The enclosure includes, but is notlimited to, a barn, greenhouse, and/or any other suitable enclosures orhousing.

In one embodiment, the term “air” as used herein shall be given itsordinary meaning, and shall include all airborne and gaseous componentsof air that has been contacted with the methane in the enclosure means,including the methane emitted by the animals contained within theenclosure means, as well as ammonia gas, dust, and/or other airbornematerials that may be present in the air.

In one embodiment, methane-consumption means includes any means by whichthe methane is oxidized, consumed, and/or otherwise used as a form ofcarbon and/or energy. Methane-consumption means includes, but is notlimited to, methane-utilizing microorganisms, fuel cells, turbines,reverse-flow reactors, engines, microturbines, and/or any othermethane-consumption means. Accordingly, in some embodiments, methaneemissions are conveyed from ruminant animals (or another source) to afuel cell, turbine, or reactor to produce fuel or other energy. Thus, insome embodiments, methanotrophic microorganisms need not be used.

In one embodiment, the ammonia contained within the air is contactedwith liquid water and converted into ammonium and used as a source ofnitrogen by the methane-utilizing microorganisms. In one embodiment, thedust and/or other airborne material within the enclosed air is reducedprior to or in the course of using the methane within the air as asource of carbon and/or energy.

In one embodiment, the methane within the air is used by themethane-consumption means in conjunction with alternative sources ofmethane, such as coal mine methane, landfill gas methane, natural gasmethane, manure digester methane, wastewater treatment methane, and/orother sources of methane.

In one embodiment, an air conveyor is provided to direct, move, and/orotherwise convey enclosure air, wherein the conveyor can be used tocontact the air with the methane-consumer. In another embodiment, aconveyer is used to move gaseous and/or methane emissions from onelocation to another, and may include pipes, tubing, containment means,ducts, channels\and other conduits. In one embodiment, the conveyer islarge and/or compartmentalized such that at least a portion of theconveyer serves as the bioreactor, in that it contains methanotrophicorganisms.

In one embodiment, the enclosure is erected, modified, and/or used toenclose the animals and to make the methane available for use by themethane-consumer. In one embodiment, the enclosure is provided andutilized to collect the air containing the methane.

In one embodiment, the methane emissions provided to the methanotrophicorganism or other methane consumption means is provided in conjunctionwith air, dust, methane, ammonia, gases, insects, particulate matter,and/or other airborne matter. In some embodiments, one of skill in theart will appreciate that one or more of the above steps described hereinis modified or omitted. Further, the steps need not be conducted in theorder set forth herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view of an apparatus used to carry out aprocess in accordance with one embodiment of the invention. In theillustration, the apparatus is self-contained and maintained entirely onthe body of a ruminant animal. FIGS. 2A, 2B, 3A, and 3B describe thisapparatus in greater detail.

FIG. 2A is a top cross-sectional view of one of two parts of theapparatus depicted in FIG. 1. The part of the apparatus illustrated isthe permanent exhalation conveyance structure that is attached to thebody of a ruminant animal.

FIG. 2B is a side perspective view of one of two parts of the apparatusdepicted in FIG. 1. The part of the apparatus illustrated is thepermanent exhalation conveyance structure that is attached to the bodyof a ruminant animal.

FIG. 3A is a side cross-sectional view of one of two parts of theapparatus depicted in FIG. 1. The part of the apparatus illustrated isthe removable microorganism containment capsule that is inserted intothe permanent exhalation conveyance structure.

FIG. 3B is a side perspective view of one of two parts of the apparatusdepicted in FIG. 1. The part of the apparatus illustrated is theremovable microorganism containment capsule that is inserted into thepermanent exhalation conveyance structure.

FIG. 4 is a schematic of a preferred embodiment of a process carried outin accordance with one embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While this invention comprises embodiments in many different forms,there will herein be described in detail preferred methods of carryingout a process in accordance with the invention with the understandingthat the present disclosure is to be considered as an exemplification ofthe principles of the invention and is not intended to limit the broadaspect of the invention to the embodiments illustrated.

In a preferred embodiment of the invention, methane emissions aretreated through the use of a product-generating methanotrophic growthsystem. In one embodiment, this growth system is designed to enable theproduction of harvestable bio-based goods. For example, in a preferredembodiment, methanotrophic microorganisms and air containing methaneemissions are mutually-exposed in an apparatus, such as a bioreactor,filled with methanotrophic bacteria, whereby methanotrophic bacteria usemethane emissions for the creation of a harvestable bio-based product.

In one embodiment, the harvestable bio-based product includes, but isnot limited to, a polymer such as polyhydroxybutyrate (PHB), single cellprotein, enzymes, homogenized biomass, and other harvestablemethanotrophic products. This process may be carried out in sterile,semi-sterile, or non-sterile conditions.

The term “harvestable” as used herein shall be given its ordinarymeaning and shall also mean usable, producible, collectable, useful,yieldable, and capable of being harvested. Likewise the term “harvest”is a broad term that shall be given its ordinary meaning and shall alsomean gather, collect, amass, accumulate, and assemble.

In one embodiment, methane emissions are captured, exposed to, andtreated with one or more species of methanotrophic microorganisms toproduce a harvestable single cell protein. Single cell protein (or SCP)includes microbial biomass or proteins containing therein or extractedtherefrom, and may be used as animal feed, for human nutrition, or forindustrial uses. One particularly suitable method for the production ofsingle cell protein is the use of a self-containing conglomerate ofmicroorganisms that promotes product and species stability innon-sterile or semi-sterile conditions. The production process used byNorferm A/S in Norway to create SCP from methane is one example of amethanotrophic growth process that may be applied to carry out oneembodiment of the present invention.

Another suitable method for the production of a harvestable product(including, but not limited to SCP) is the use of methods to promoteproduct stability and harvestability. These methods include, but are notlimited to: air disinfection, water disinfection, mineral mediadisinfection, system sterility management, directed species symbiosis,growth conditions management, incoming air gaseous componentsseparation, and others. Accordingly, in one embodiment, productstability and/or harvestability is enhanced or facilitated by one ormore of these methods.

In another embodiment of the invention, methane emissions are used toeffect the growth of microorganisms, wherein microorganisms aresubsequently manipulated to produce harvestable PHB by deprivingmicroorganisms of a particular nutrient, such as nitrogen, on a batch,semi-batch, or continuous basis. Methanotrophic microorganisms (such asAlcaligenes eutrophus) employ a polymer (such as PHB) as a form of anenergy storage molecule to be metabolized when other common energysources are not available. Thus, in one embodiment, methanotrophicorganisms are periodically or continuously exposed to methane emissionsin a nitrogen-poor environment. Partial, substantial, or completedepletion of nitrogen can occur before the organisms are exposed tomethane or after such exposure has occurred. Alternatively, nitrogendepletion can occur at some point during exposure of the organisms tomethane. As is well known in the art of microbial PHA and PHBproduction, the depletion of an essential nutrient such as nitrogen inthe presence of a sufficient carbon supply will cause bacterial culturesto store energy in the form of PHA, PHB, or, depending on growthconditions, some similar energy storage material, with the aim ofaccessing this stored energy once all essential growth and reproductioncomponents are fully present at a later time. PHB, or similar energystorage materials, may account for a significant percentage of theweight and/or volume of a single microorganism cell, and may beharvested by any number of well known techniques, such ascentrifugation, cell lysis, homogenization, chloroform dissolution,sodium hydroxide dissolution, cell parts extraction, and so on.

In another embodiment of the invention, methanotrophic microorganismsare used to oxidize a quantifiable, monitored, and certifiable volume ofmethane in a sterile or non-sterile environment, thereby creating agreenhouse gas reduction product which may be “harvested” and sold in amarket which purchases and/or trades greenhouse gas reduction credits,such as a carbon dioxide credit trading market. Thus, in one embodiment,the harvestable product is the quantifiable reduction of methane,especially as it pertains to air pollution reductions credits and/orglobal warming gas emissions reductions credits. Accordingly, in oneembodiment of the invention, a system to quantify how much methane hasbeen used is provided. This embodiment will be particularly advantageousfor those organizations that need to comply with certain environmentalregulations or need to certify that specific volumes of methane havebeen biologically oxidized.

In another embodiment of the invention, methane emissions may be used tocreate harvestable enzymes. In one embodiment, the enzyme is methanemonooxygenase. In one embodiment, the cell contents may be accessedphysically, chemically, enzymatically, or otherwise to enable harvestingin defined or non-defined microbial cultures. The maintenance of copperconcentrations will be useful to effect the consistent production ofeither soluble or particulate methane monooxygenase, as is well known inthe art. In particular, if the concentration of copper in amethanotrophic growth medium is minimized and kept below specific andwell known concentrations, such as 5×10⁻⁹ M, the production of solublemethane monooxygenase may be effected in most or all methanotrophiccells accessing that copper-limited medium. Soluble or particulatemethane monooxygenase may be harvested using any well known methanemonooxygenase extraction and purification method.

The processes disclosed herein may be carried out and directed in acontrolled bioreactor, wherein liquid, semi-liquid, particulate, orsolid mineral media may be used to enhance the growth of methanotrophicmicroorganisms. Alternatively, the processes described herein may becarried out in reaction tanks, vessels, or other containment systems.

In another aspect of the invention, various processing techniques knownin the art may be used to preferentially extract harvestable products ofmethanotrophic growth, such as chemical treatment, centrifugation,drying, and homogenization.

In a preferred embodiment of the invention, landfill gas is used as thesource of methane. In one embodiment, impurities from landfill gas, suchas non-methane and/or volatile organic compounds, water vapor, and/orcarbon dioxide are partially, substantially, or completely removed. Inanother embodiment, the landfill gas is disinfected.

In one embodiment, UV treatment is used to disinfect the gas.Mechanical, activated carbon, or chemical filtration may also be used.

In one embodiment methane emissions within landfill gas are exposed tomethanotrophic microorganisms. In one embodiment, gaseous emissionscomprising methane are fed into a bioreactor containing methanotrophicmicroorganisms suspended in or on a liquid, semi-liquid, or solidgrowth-culture medium containing water and mineral salts. In anotherembodiment, after methanotrophic microorganisms have grown andreproduced using methane emissions as a source of carbon and/or energy,these microorganisms are harvested as single cell protein throughvarious extraction and de-watering processes.

In one embodiment, a method of treating gaseous emissions (e.g.,landfill gas) is provided. In one embodiment, the method comprises: (i)enclosing the landfill gas in a bioreactor containing methanotrophicmicroorganisms; and (ii) harvesting the microorganisms and/or theproducts produced by the microorganisms in the bioreactor. In anotherembodiment, the method comprises: (i) removing impurities from thelandfill gas; (ii) disinfecting the landfill gas; (iii) enclosing thelandfill gas in a bioreactor containing methanotrophic microorganisms;and (iv) harvesting the microorganisms and/or the products produced bythe microorganisms in the bioreactor.

In one embodiment, a portion of the microorganisms may be directed intoa bioreactor containing a nitrogen depleted growth medium and a constantsupply of gaseous emissions (e.g., landfill gas), whereby microorganismssynthesize intracellular PHB. In one embodiment, the PHB-filled cellsare subsequently removed from the reactor in order to process andharvest intracellular PHB. These processes are preferentially carriedout on a continuous, semi-continuous, semi-batch, or batch-wise basis,and methane emissions from any source, including landfills, coal mine,wastewater treatment plants, agricultural systems, or petroleum systems,may be used.

The term “methanotrophic microorganisms” refers to any microorganismsthat utilize methane as a source of carbon and/or energy for growth andreproduction, including naturally-occurring and/or geneticallyengineered microorganisms. It also refers to the combination or mixtureof methanotrophic and non-methanotrophic microorganisms that promote thegrowth of methanotrophic microorganisms. In one preferred embodiment,this combination comprises Methylococcus capsulatus, Alcaligenesacidovorans, Bacillus firmus, and Bacillus brevis, since thiscombination has been shown to limit or reduce bacterial contamination innon- and semi-sterile bioreactor conditions, thereby enabling stableproduct formation. In another preferred embodiment, this combinationcomprises any methanotrophic microorganisms that may be used to producepolymers such as PHB, enzymes such as methane monooxygenase, and/or anyother cellular components. In another preferred embodiment, thiscombination comprises a non-defined mix of methanotrophic andnon-methanotrophic microorganisms that can be used to create aharvestable product from the oxidation (or alternate processing) ofmethane emissions.

The terms “methanotrophic microorganism growth-culture medium” and“growth medium” refer to any medium promoting the growth ofmicroorganisms, including any one or more of the following: liquid,semi-liquid, gas, particulate, ceramic, foam, plastic, alginate gel,methanol-enriched, copper-enriched, clay, nutrient, or other appropriategrowth-culture medium. In a preferred embodiment, this growth culturemedium comprises an aqueous solution containing mineral salts, copper,and other trace minerals necessary for the growth and reproduction ofmethanotrophic bacteria.

In another preferred embodiment, a system comprising methanotrophicorganisms is used to degrade or otherwise reduce a pollutant other thanmethane as a method to enable the viable treatment of methane emissions.In one embodiment, the growth of methanotrophic microorganisms usingmethane emissions is carried out in the presence of a non-methanematerial that can be broken-down, oxidized, consumed, and/or otherwisechanged in form through the action of such microorganisms, wherein suchnon-methane material includes, but is not limited to, one or more of thefollowing: toluene, benzene, methanol, propylene, any alkenes, alcohols,ethers, alicyclics, aromatics, and/or chlorinated organic compounds,such as the pollutant TCE, wherein a product, including the oxidizedchemical or quantifiable pollutant treatment, may be harvested in acontrolled, directed, and/or quantifiable manner.

In another preferred embodiment of the invention, following the growthof methanotrophic microorganisms in a bioreactor, some or all of thecontents of the bioreactor are removed from the bioreactor and areeither processed or used and sold directly. Processing may include anynumber of methods that enable product harvest, such as centrifugation,filtration, drying, homogenization, chemical treatment, physicaltreatment, enzymatic treatment, or any other processing means.Processing means may be used to extract products out of defined ornon-defined conglomerates of methanotrophic microorganisms. Theapplication and utilization of processing techniques, such ascentrifugation and homogenization, may be used to effect the overallharvestability of the methanotrophic growth and treatment process,especially where the maintenance of a defined culture is unfeasible.

Preferred embodiments of the present invention offer one or moreadvantages. For example, one or more embodiments provide one or more ofthe following benefits:

(i) enables the viable and economical utilization of methanotrophicmicroorganisms in the treatment and utilization of methane emissions;

(ii) enables methanotrophic methane emissions treatment withoutdepending on a reduction in capital or operating costs;

(iii) enables the viable and economical application of methanotrophicmicroorganisms to methane emissions treatment in environments where areduction in the concentration of methane emissions is not required;

(iv) provides a methanotrophic methane emissions treatment process thatis economically competitive with alternative methods of methaneemissions treatment;

(v) provides a process that applies well-known methods of harvestablemethanotrophic product-generation as a novel method to enable thesustained treatment and utilization of methane emissions;

(vi) overcomes previously insurmountable practical challenges in thefield of methane emissions treatment; and/or

(vii) provides a process which, if widely applied, has the capacity tosignificantly reduce global methane emissions.

Preferred embodiments of the invention comprise one or more of theforegoing advantages and/or objects. Further objects and advantages willbecome apparent from the ensuing description.

In another preferred embodiment, methane emissions may be used fromlandfills, coal mines, wastewater treatment plants, manure digesters,agricultural digesters, compost heaps, enclosed agricultural feedlots,leaking or otherwise emitting petroleum systems, and any other source ofmethane emissions or off-gas whereby the creation of harvestablebio-based is enabled. The methane emitted by ruminant animals can alsobe used as a source of methane according to several embodiments of thepresent invention. The processing of methane emissions produced byruminant animals is discussed below.

Prior to the applicants' discovery, no methods were known to reduceruminant animal methane emissions by using such methane as a source ofenergy in energy consumption systems maintained outside of the digestivetracts of ruminant animals. In the past, all ruminant animal methanereduction processes have focused on limiting ruminant animal methaneproduction rather than reducing overall atmospheric emissions through asystem of methane utilization. Thus, it is one feature of severalembodiments of the present invention that ruminant methane emissions arereduced through the utilization of ruminant animal methane as a sourceof energy. No methods are believed known to capture and/or consolidateenteric fermentation methane emissions in a way that would convert theminto a state suitable for use as a fuel stream for the production ofmethane-based goods or processes. Enteric fermentation methaneoriginates as diffuse emissions, and no methods are known to convertsuch emissions into a usable form. For these and other reasons, ruminantanimal methane emissions have never been considered as a viable sourceenergy, and the connection between enteric fermentation methaneemissions and methane-driven process and goods production has neveroccurred.

Mechanical ventilation systems are well known in the livestock andagricultural science art for their capacity to draw, push, or pull airthrough a fully or partially enclosed ruminant animal holding, feeding,or enclosure area. The main function of mechanical ventilation systems,including tunnel ventilation systems and other ventilation systems, isto provide air flow or air exchange in order to maintain or improve thehealth of ruminant animals in a fully or partially enclosed holding orfeeding area. It is also well known in the livestock and agriculturalscience art that some mechanical ventilation systems, particularlytunnel ventilation systems, have the capacity to force all or some ofthe air inside a fully or partially enclosed ruminant animal holding orfeeding area through specific vents or fans. The outflow air coming outof ventilation fans have even been forced, directed, or led into mulch,compost, and/or other platforms designed to limit or reduce outflow airodor or dust emissions. Prior to the applicants' discovery, though, suchventilation systems used in conjunction with enclosure structures hadnever been considered as means to enable the capture, consolidation, andutilization of ruminant animal methane emissions as a source of energy.It is one feature of several embodiments of the present invention thatanimal enclosure structures and/or ventilation systems are applied asmeans to capture, consolidate, direct, and/or convey ruminant animalmethane emissions to enable the use of such emissions as a source ofenergy. Prior to the applicants' discovery, ventilation systems and/orenclosure structures had never been used to capture ruminant animalenteric fermentation methane emissions, nor had such emissions ever beenused to grow bacteria in a bioreactor optionally equipped with means toharvest any of the microbial products associated with bioreactoractivity, particularly microbial biomass.

Further, prior to the applicants' discovery, ventilation systems and/orenclosure structures had never been used to capture enteric fermentationmethane for utilization by a methane-consumption system such as areverse-flow reactor or microturbine. The utilization of air conveyancesystems to capture enteric fermentation methane for use as a source ofcarbon and/or energy overcomes a range of practical problems associatedwith a system for capturing methane emissions from the nose and/or mouthof a ruminant animal using on-animal apparatuses such as bioreactors ormicroturbines, including animal mobility problems and reactor sizerequirements for optimal methane conversion. The straightforwardutilization of structures, means, and systems that are well known and/orcommonly used also overcomes a range of prior emissions captureproblems, including practicability, palatability, and viability. One ofskill in the art will understand that currently available and otherventilation systems can be used in accordance with embodiments of theinvention.

As described herein, several embodiments of the present inventionprovide a novel process for the utilization of methane emitted byruminant animals. Preferred embodiments of the invention involvingruminant animal emissions are particularly advantageous because theyprovide one or more of the following benefits:

(i) converts a previously wasted form of energy into a usefulend-product,

(ii) converts an environmentally-destructive greenhouse gas into auseful end-product,

(iii) provides a direct economic incentive for a ruminant animal methaneemissions reduction effort,

(iv) reduces atmospheric ruminant animal methane emissions withoutaltering the chemical or microbial make-up of the digestive tract ofruminant animals,

(v) reduces atmospheric ruminant animal methane emissions withoutrequiring ruminant animals to alter their normal/natural behaviorpatterns, including sleeping and nutrient-consumption,

(vi) reduces atmospheric ruminant animal methane emissions withoutrequiring feed reformulations, selective breeding activities, orchemical or microbial modifications to the digestive systems of ruminantanimals,

(vii) utilizes as a source of energy a material never previouslyconsidered a viable source of energy, and/or

(viii) has the potential, especially if used widely, to significantlyreduce ruminant animal methane emissions.

As used herein, the terms “ruminant animal methane”, “entericfermentation methane”, and “ruminant animal enteric fermentationmethane” shall be given their ordinary meaning and shall also refer toany methane produced and emitted by one or more ruminant animals as aresult of processes associated with enteric fermentation. An averageadult dairy cow will emit approximately 150 kg of enteric fermentationmethane per year, while beef cattle will each produce about two-thirdsof that volume, or 100 kg per year. Methane emitted by ruminant animalsis a particularly important greenhouse gas, since on a ton-to-ton basisit has 21 to 23 times the heat-trapping capacity of carbon dioxide.

The term “consolidation means” shall be given its ordinary meaning andshall also refer to any means by which enclosure air is unified,mutually-directed, and/or otherwise consolidated for conveyance. In onepreferred embodiment, a consolidation means comprises an air-tightducting tube running from an air outlet to a mutual-exposure means, asdescribed below, wherein enclosure air is directed out of an enclosedarea, through a consolidation means, and into a mutual-exposure means.In another preferred embodiment, a consolidation means comprisesmultiple ducting tubes connected to air outlets and situated toconsolidate outflowing enclosure air into a single ducting tube thatultimately leads as one or more air streams into a methane-consumptionsystem.

The term “ventilation means” shall be given its ordinary meaning andshall also refer to any means by which air, gases, and/or other airbornematerial is mechanically forced, pushed, pulled, drawn, moved, conveyed,or otherwise directed into, through, and/or out of a spatial areaenclosed by an enclosure means. In one preferred embodiment, well-knownventilation fans, such as rotating ventilation fans and/or tunnelventilation fans, operate in a well-known barn ventilation process,whereby air may be drawn into a barn through one or more open spaces ina barn wall and directed out of a barn through ventilation fans. In onepreferred embodiment, an enclosure means is provided with ventilationmeans, wherein air is moved into and out of an enclosure means at anoverall combined rate of 10 cubic feet per minute per dairy cow. In onepreferred embodiment, means for the cooling of barn-enclosed air arealso provided in order to ensure animal well-being in an enclosed area.A number of air-cooling means are well known, such as cooling pads,water sprayers, and air conditioning units.

The term “ruminant animal” shall be given its ordinary meaning and shallalso refer to one or more ruminant animals, including, as in onepreferred embodiment, a dairy or beef cow.

The terms “enclosure means” and “means for enclosure” shall be giventheir ordinary meaning and shall also refer to any means by which someor all of the space in which one or more ruminant animals exist ispartially or fully confined, isolated, encapsulated, and/or enclosed,such as a barn or greenhouse structure. In one preferred embodiment, abarn with a specified air inlet, such as a window, and a specified airoutlet, such as a window housing a ventilation fan, encloses a ruminantanimal (e.g., dairy cow).

The term “air inlet” shall be given its ordinary meaning and shall alsorefer to any location where air, gas, and/or other airborne materialenters into an area or chamber fully or partially enclosed by anenclosure means. In one preferred embodiment, an air inlet comprises aspatial opening, such as a window, in the wall of an enclosure means.

The term “air outlet” shall be given its ordinary meaning and shall alsorefer to any location where air, gas, and/or other airborne materialexits out an area or chamber fully or partially enclosed by an enclosuremeans. In one preferred embodiment, an air outlet comprises a spatialopening housing a ventilation means located in the wall of an enclosuremeans.

The term “enclosure air” shall be given its ordinary meaning and shallalso refer to the air, gases, and/or other airborne material that havebeen mixed with enteric fermentation methane in the space fully orpartially enclosed by an enclosure means, including enteric fermentationmethane, ammonia, dust, and/or other airborne material contained withinan enclosure means containing a ruminant animal.

Methane-utilizing microorganisms represent one embodiment of a“methane-consumption system” or “methane consumption means.” The lattertwo terms include a biological system that utilizes enteric fermentationmethane as a source of carbon and/or energy, a mechanical system thatuses or consumes methane, and/or a chemical system that uses, degrades,consumes, or reacts with methane.

The term “methane-utilizing microorganism” or “methanotrophicmicroorganism” shall be used interchangeably, shall be given theirordinary meaning, and shall also refer to any microorganism,naturally-occurring or genetically-engineered, that utilizes methane,including enteric fermentation methane, as a source of carbon and/orenergy. The term “methane-utilizing microorganisms” also refers to thecombination of methane-utilizing and non-methane-utilizingmicroorganisms that are collectively associated with the growth ofmethane-utilizing microorganisms. In one embodiment, this microorganismcombination includes one or more of the following: Methylococcuscapsulatus, Alcaligenes acidovorans, Bacillus firmus, and Bacillusbrevis. In one embodiment, a combination of these microorganisms is usedbecause among other advantages, this combination is known to promote thelong-term growth of Methylococcus capsulatus. The term“methane-utilizing microorganisms” also includes any methanotrophicorganisms and organisms that use or “take-up” methane. Methane-utilizingmicroorganisms may be confined in a microorganism holding tankcontaining methane-utilizing microorganisms and a microorganismgrowth-culture medium. They may also be present in a biofiltrationsystem containing methane-utilizing microorganisms whereinmicroorganisms either are or are not attached to a microorganism supportsubstrate and are continuously or intermittently contacted with amicroorganism growth-culture medium. They may also be used in abioreactor containing methane-utilizing microorganisms and amicroorganism growth-culture medium wherein the growth-culture medium isin liquid, foam, solid, semi-solid, or any other suitable form andmethane-utilizing microorganisms are naturally-occurring and/orgenetically engineered and may or may not have been selectively insertedas part of a pre-determined microbial consortium. While the use ofspecified microorganism consortium may provide some benefits, anon-specified and naturally-equilibrating consortium of one or moremicroorganisms may also be employed. Typical examples ofmethane-utilizing microorganisms useful in several embodiments of thepresent invention include, but are not limited to, bacteria and yeast.

Suitable yeasts include species from the genera Candida, Hansenula,Torulopsis, Saccharomyces, Pichia, 1-Debaryomyces, Lipomyces,Cryptococcus, Nematospora, and Brettanomyces. The preferred generainclude Candida, Hansenula, Torulopsis, Pichia, and Saccharomyces.Examples of suitable species include: Candida boidinii, Candidamycoderma, Candida utilis, Candida stellatoidea, Candida robusta,Candida claussenii, Candida rugosa, Brettanomyces petrophilium,Hansenula minuta, Hansenula saturnus, Hansenula californica, Hansenulamrakii, Hansenula silvicola, Hansenula polymorpha, Hansenulawickerhamii, Hansenula capsulata, Hansenula glucozyma, Hansenulahenricii, Hansenula nonfermentans, Hansenula philodendra, Torulopsiscandida, Torulopsis bolmii, Torulopsis versatilis, Torulopsis glabrata,Torulopsis molishiana, Torulopsis nemodendra, Torulopsis nitratophila,Torulopsis pinus, Pichia farinosa, Pichia polymorpha, Pichiamembranaefaciens, Pichia pinus, Pichia pastoris, Pichia trehalophila,Saccharomyces cerevisiae, Saccharomyces fragilis, Saccharomyces rosei,Saccharomyces acidifaciens, Saccharomyces elegans, Saccharomyces rouxii,Saccharomyces lactis, and/or Saccharomyces fractum.

Suitable bacteria include species from the genera Bacillus,Mycobacterium, Actinomyces, Nocardia, Pseudomonas, Methanomonas,Protaminobacter, Methylococcus, Arthrobacter, Methylomonas,Brevibacterium, Acetobacter, Methylomonas, Brevibacterium, Acetobacter,Micrococcus, Rhodopseudomonas, Corynebacterium, Rhodopseudomonas,Microbacterium, Achromobacter, Methylobacter, Methylosinus, andMethylocystis. Preferred genera include Bacillus, Pseudomonas,Protaminobacter, Micrococcus, Arthrobacter and/or Corynebacterium.Examples of suitable species include: Bacillus subtilus, Bacilluscereus, Bacillus aureus, Bacillus acidi, Bacillus urici, Bacilluscoagulans, Bacillus mycoides, Bacillus circulans, Bacillus megaterium,Bacillus licheniformis, Pseudomonas ligustri, Pseudomonas orvilla,Pseudomonas methanica, Pseudomonas fluorescens, Pseudomonas aeruginosa,Pseudomonas oleovorans, Pseudomonas putida, Pseudomonas boreopolis,Pseudomonas pyocyanea, Pseudomonas methylphilus, Pseudomonas brevis,Pseudomonas acidovorans, Pseudomonas methanoloxidans, Pseudomonasaerogenes, Protaminobacter ruber, Corynebacterium simplex,Corynebacterium hydrocarbooxydans, Corynebacterium alkanum,Corynebacterium oleophilus, Corynebacterium hydrocarboclastus,Corynebacterium glutamicum, Corynebacterium viscosus, Corynebacteriumdioxydans, Corynebacterium alkanum, Micrococcus cerificans, Micrococcusrhodius, Arthrobacter rufescens, Arthrobacter parafficum, Arthrobactercitreus, Methanomonas methanica, Methanomonas methanooxidans,Methylomonas agile, Methylomonas albus, Methylomonas rubrum,Methylomonas methanolica, Mycobacterium rhodochrous, Mycobacteriumphlei, Mycobacterium brevicale, Nocardia salmonicolor, Nocardia minimus,Nocardia corallina, Nocardia butanica, Rhodopseudomonas capsulatus,Microbacterium ammoniaphilum, Archromobacter coagulans, Brevibacteriumbutanicum, Brevibacterium roseum, Brevibacterium flavum, Brevibacteriumlactofermentum, Brevibacterium paraffinolyticum, Brevibacteriumketoglutamicum, and/or Brevibacterium insectiphilium.

The term “microorganism growth-culture medium” shall be given itsordinary meaning and shall also refer to any medium promoting the growthof microorganisms. It shall also refer to any substrate, aside frommethane, which microorganisms oxidize or otherwise break down. It shallalso refer to any substrate or material that concentrates methane,preferentially sequesters methane, “traps” methane, increases thesolubility and/or availability of methane, and/or otherwise enables theenhanced breakdown, oxidation, and/or utilization of methane bymicroorganisms. The term “microorganism growth-culture medium” includes,but is not limited to, any substrate and/or microorganism immobilizationmeans, such as liquid, semi-liquid, gas, particulate, ceramic, foam,plastic, alginate gel, methanol-enriched, copper-enriched, clay,nutrient, or other appropriate growth-culture medium. In one preferredembodiment, this growth culture medium comprises aqueous solutioncontaining water, nitrogen, ammonium, trace minerals, and otherwell-known microorganism growth-culture medium components necessary forthe growth and reproduction of methane-utilizing bacteria. In anotherpreferred embodiment, this growth culture medium comprises amicroorganism immobilization means, such as organic or inorganicparticles, on which a liquid or semi-liquid mineral medium solution iscontinuously or periodically contacted and on which microorganisms areattached. In another preferred embodiment, this growth-culture mediumcomprises waste organic materials, which methane-utilizingmicroorganisms may or may not break down to produce a byproduct oforganic materials that may or may not be useful. In another preferredembodiment, this growth-culture medium comprises a liquid foamsubstrate.

In yet another preferred embodiment, the growth-culture medium iscombined with various materials which methane-utilizing microorganismsmay or may not convert to more desirable materials. Examples of variousmaterials include, but are not limited to, toluene, trichloroethylene(TCE), propylene, and agricultural byproduct materials whichmicroorganisms may preferentially breakdown or oxidize.

In one embodiment, the invention comprises conveying entericfermentation methane to an apparatus situated entirely on the body of aruminant animal which mutually-exposes methane-utilizing microorganisms,enteric fermentation methane, and a microorganism growth-culture medium,causing methane-utilizing microorganisms to grow using entericfermentation methane as a source of carbon and/or energy. Preferredembodiments of the invention are described below and illustrated byFIGS. 1, 2, and 3.

FIG. 1 is a side perspective view of an apparatus used to carry out aprocess in accordance with the invention. In this illustration, all ofthe means necessary for carrying out a process in accordance with theinvention are maintained and situated entirely on the body of ruminantanimal, including means for conveying ruminant animal exhalation, andthe exhalation methane therein, to a means for mutually-exposing entericfermentation methane, methane-utilizing microorganisms, and amicroorganism growth-culture medium, as well as a means for harvestingthe product of methane-utilizing microorganism growth. In otherembodiments, one or more components are not located on the animal, butinstead are coupled to or in communication with the animal.

In FIG. 1, exhalation collection tubes 15 a and 15 b are situated one oneither side of the head of ruminant animal 14. Tubes 15 a and 15 b areheld in place by stationary head harness 16 and lead up to the nostrilsof ruminant animal 14. Tubes 15 a and 15 b run from the nostrils ofruminant animal 14 to where they both converge into exhalationcollection tube convergence T-pipe 18. T-pipe 18 connects to exhalationinflow tube 19, which leads into permanent exhalation conveyancestructure 20. Structure 20 is described in further detail by FIGS. 2Aand 2B. Structure 20 is held in place on the back of ruminant animal 14by stabilizing leg straps 17 a, 17 b, 17 c, and 17 d, as illustrated.

FIG. 2A is a top cross-sectional view of structure 20, and FIG. 2B is aside perspective view of structure 20. Tube 19 passes through air pumphousing front wall 29 and leads into exhalation flow pipe chamber 43.Inside chamber 43, tube 19 connects to inflow pump chamber tube 21,which leads through chamber 43, through air pump housing middle wall 30,and into diaphragm-enclosed chamber 23. Where tube 21 opens into chamber23 is inflow one-way flap sphincter 22, which, being a one-way flap,allows air to travel into chamber 23, but does not allow air to travelfrom chamber 23 into tube 21.

Chamber 23 is enclosed by rubber diaphragm 44. The open end of diaphragm44 is attached to wall 30 so that an air-tight seal is made, and chamber23 is formed. Diaphragm pump plunger 31 is inserted through and intodiaphragm 44 on the side of diaphragm 44 farthest from wall 30. Plunger31 extends out of diaphragm 44 to where it is joined perpendicularly torotational gear tooth 32, which is attached to rotational gear 33. Gear33 is mounted on motor axle 36, which leads into direct-currentrotational motor 34. Motor 34 is located inside exhalation motor pumpingchamber 45. Positive motor electrical terminal 46 is connected topermanent structure positive conduction plate 37 by positive electricalconduction wire 35. Negative motor electrical terminal 47 is connectedto permanent structure negative conduction plate 38 by negativeelectrical conduction wire 48. Plate 37 and plate 38 are mounted on airpump housing back wall 27 with portions of each plate protruding throughand outside of wall 27. Connected to the end of plate 37 on the endfarthest from chamber 45 is positive conduction continuation spring 39.Connected to the end of permanent structure negative conduction plate 38on the end farthest from chamber 45 is negative continuation spring 40.Structurally, an electric current can now flow from spring 39 toterminal 46 as well as from spring 40 to terminal 47.

Returning to chamber 23, outflow one-way flap sphincter 24 leads outfrom chamber 23 and into outflow pump chamber tube 25. Sphincter 24allows air to travel out of chamber 23, but it does not allow air totravel from tube 25 into chamber 23. Tube 25 runs from chamber 23,through wall 30, and through chamber 43 to where it finally connectswith outflow insertion needle 26. Needle 26 runs from the inside ofchamber 43, protrudes through wall 27, and extends beyond wall 27directly away from tube 19. Needle 26 is open on the end farthest fromtube 25.

Half-cylindrical shell 42 is attached to wall 27. The orientation ofshell 42 is depicted in FIG. 2B. Running the length of shell 42 isinlaid guidance groove 41. As will be described later, groove 41 has thepurpose of guiding removable microorganism containment capsule 99 intocorrect orientation with needle 26, spring 39, and spring 40. Capsule 99is described in greater detail in FIGS. 3A and 3B.

FIG. 3A and FIG. 3B depict capsule 99. Specifically, FIG. 3A is a sidecross-sectional view of capsule 99, and FIG. 3B is a side perspectiveview of capsule 99. Structure 20 is designed to support and feedruminant animal exhalation (and the methane contained therein) intocapsule 99. Designed accordingly, capsule 99 is described in threeparts: threaded inflow attachment pipe 60, threaded outflow attachmentpipe 62, and microorganism growth capsule pipe 80. Capsule 99, as awhole, consists of each of these three pieces connected together, aswill be described.

Pipe 80 is threaded on the outer side of both ends and containsmethane-utilizing microorganisms 92 and microorganism growth-culturemedium 93. In the present embodiment, 5 grams of Methylococcuscapsulatus, methane-utilizing microorganisms which can be obtained froma number of biological supply depots (including Chang Bioscience,located at 125 Cambon Drive #6H, San Francisco, Calif. 94132) are placedin an aqueous microorganism growth-culture medium containing ammonium,nitrogen, and mineral salts.

Attached to one end of pipe 80 is pipe 60. Attached on the other end ofpipe 80 is pipe 62. Pipe 60 houses D-size battery 75, which is situatedbetween removable capsule positive electrical conduction terminal 70,removable capsule negative electrical conduction plate 74, and inflowattachment pipe inner wall 76. Plate 74 rests against wall 76 and sitsadjacent to battery 75. Terminal 70 sits adjacent to battery 75 andprotrudes through the front side of pipe 60. Similarly, terminal 71protrudes through the front side of pipe 60 from the inside of pipe 60.Capsule negative electrical conduction wire 49 runs from terminal 71 toplate 74. Running from the outer edge of the front side of pipe 60,passing through wall 76, and extending beyond wall 76 into pipe 80 isair dispersion capillary tube 72. Tube 72 is a solid tube except for theportion extending into pipe 80, which contains tiny capillary holes inits walls that allow air to pass out of tube 72 but do not allow medium93 to pass into tube 72. Tube 72 is open at the end meeting the outeredge of the front side of pipe 60, and closed at its opposite end.Attached to the outside of pipe 60 is inflow guidance ridge 89, a solidpiece of material which will eventually fit into groove 41 illustratedin FIG. 2A and FIG. 2B.

Attached to pipe 80 on the end opposite pipe 60 is pipe 62. Pipe 62 isan elbow-shaped pipe that allows air to escape after it has passedthrough the small holes in the walls of tube 72. Pipe 62 is a hollowpiece of piece of pipe at the end where it is connected to pipe 80,though, at its other end, pipe 62 is a solid piece of pipe. Wire meshgrating 61 is located inside pipe 62 at the border of where pipe 62turns from hollow to solid. Still inside of pipe 62, adjacent to grating61 in the solid portion of pipe 62, leak prevention holes 63 a and 63 bare drilled through the solid piece of pipe 62. Inside of hole 63 a areplug balls 64 a and 64 b. Inside of hole 63 b are plug balls 64 c and 64d. Balls 64 a, 64 b, 64 c, and 64 d are rubber balls which can float onthe surface of medium 93. Holes 63 a and 63 b are partially blocked atboth the ends farthest and the ends closest to the hollow portion ofpipe 62. Holes 63 a and 63 b are partially blocked by grating 61 at theend closest to the hollow portion of pipe 62. While the diameters ofholes 63 a and 63 b are constant throughout, the diameters decrease atthe ends farthest from the hollow portion of pipe 62 such that a singleball (64 a or 64 c) cannot pass through that end. Similar to ridge 89,outflow guidance ridge 90, which is able to slide into groove 41, islocated on the outside of pipe 62.

The following is a description of one method by which an apparatus isused to carry out a process in accordance with one embodiment of theinvention.

First, structure 20 is situated on the back of ruminant animal 14 usingstraps 17 a, 17 b, 17 c, and 17 d. Next, harness 16 is attached to thehead of ruminant animal 14, and tubes 15 a and 15 b are connected toharness 16 such that tubes 15 a and 15 b lead from T-pipe 18 up to thenostrils of ruminant animal 14.

Second, capsule 99 is placed into shell 42 of structure 20. This isaccomplished by inserting ridge 89 and ridge 90 on capsule 99 intogroove 41 inlaid in shell 42 of structure 20. With capsule 99 alignedwith structure 20, capsule 99 is slid towards wall 27 up to the pointwhere needle 26 is inserted into tube 72, and spring 39 and spring 40are placed, respectively, into contact with terminal 70 and terminal 71.With terminal 70 and terminal 71 placed into contact with spring 39 andspring 40, respectively, an electrical current now runs from battery 75in capsule 99 to motor 34 in structure 20. Specifically, a positiveelectrical current runs from battery 75, through terminal 70, throughspring 39, through plate 37, though wire 35, to terminal 46. A negativeelectrical current runs from battery 75, through plate 74, through wire49, through terminal 71, through spring 40, through plate 38, throughwire 48, to terminal 47.

With an electrical current running from battery 75 to motor 34, axle 36on motor 34 begins to rotate rapidly. As axle 36 rotates, gear 33 andgear tooth 32 also rotate rapidly, which in turn causes plunger 31 torapidly push and pull diaphragm 44. With diaphragm 44 oscillatingtowards and away from wall 30, the motion of diaphragm 44 causes air toflow from tubes 15 a and 15 b, into chamber 23, and into needle 26. Toexpand, air is pulled through tubes 15 a and 15 b, through T-pipe 18,through tube 19, through tube 21, past sphincter 22, through chamber 23,past sphincter 24, through tube 25, and into needle 26.

With capsule 99 inserted, as described above, into structure 20, air nowtravels from needle 26 into tube 72. Since tube 72 is blocked at the endlocated in pipe 80 and since air cannot travel from tube 72 back intochamber 23, air is forced out through the tiny holes which exist in thewalls of tube 72. To reiterate a detail mentioned above, in oneembodiment, tiny holes exist in the walls of tube 72 only where tube 72extends into pipe 80. The result is that air is conveyed from needle 26,through tube 72, and into pipe 80. Eventually, with no other means ofescape, the air inside pipe 80 flows into the hollow portion of pipe 62,past grating 61, into holes 63 a and 63 b, past plug balls 64 a, 64 b,64 c, and 64 d, out of holes 63 a and 63 b.

The result of this conveyance of air is that as ruminant animal 14exhales, this exhalation, as well as exhalation methane therein, isconveyed and directed into tubes 15 a and 15 b, which are situated justabove the nostrils of ruminant animal 14. Exhalation methane now travelsthrough tubes 15 a and 15 b to needle 26. With capsule 99 inserted, asdescribed above, into structure 20, exhalation methane of ruminantanimal 14 travels through needle 26 into pipe 80.

Pipe 80 contains microorganisms 92 and medium 93, and when exhalationmethane is conveyed into pipe 80, microorganisms 92 grow and reproduceusing this exhalation methane as a source of carbon and/or energy. Putdifferently, exhalation methane, microorganisms 92, and medium 93 aremutually-exposed in pipe 80. Thus, as more exhalation methane fromruminant animal 14 is exposed to microorganisms 92 in medium 93,microorganisms 92 grow and reproduce using exhalation methane as asource of carbon and/or energy. All excess gases, including waste carbondioxide and waste exhalation methane, exit capsule 99 as describedabove.

Although medium 93 is an aqueous medium, holes 63 a and 63 b, balls 64a, 64 b, 64 c, and 64 d, and grating 61 act together to prevent medium93 from spilling or escaping out of capsule 99. Specifically, since plugballs 64 a, 64 b, 64 c, and 64 d are designed to float on the surface ofmedium 93, if medium 93 travels past grating 61 and moves into holes 63a and/or 63 b, balls 64 a and 64 c will plug the small-diameter end ofholes 63 a and 63 b, respectively, before the aqueous medium 93 can passout of capsule 99.

The process continues when, after a certain amount of time (in thisembodiment approximately 7 days) it is determined that microorganisms 92within capsule 99 are no longer growing at optimal rates or have stoppedgrowing completely, and capsule 99 is removed from structure 20. Themicroorganism growth process is re-started and continued simply byreplacing previously-used capsule 99 with a new apparatus structurallyidentical to capsule 99 containing new methane-utilizing microorganismsand a new microorganism growth-culture medium. The process may also becontinued by re-using capsule 99 and, after removing all or most ofmicroorganisms 92 and medium 93, filling it with new microorganismgrowth-culture medium and an optimal number of new or previously usedmethane-utilizing microorganisms. In such a manner, exhalation methaneis continually used as a source of carbon and/or energy for the growthand harvesting of methane-utilizing microorganisms.

Finally, microorganisms 92, having been grown in capsule 99 usingexhalation methane as a source of carbon and/or energy, are removed fromcapsule 99 and harvested as useful biomass. (Methylococcus capsulatushas a biomass which consists of about seventy percent protein byweight). Such biomass can be processed and sold as a nutritionalfoodstuff or converted into other useful products, such as adhesives orcosmetics.

In one preferred embodiment, as detailed by FIG. 4, “mutual-exposuremeans” shall be given its ordinary meaning and shall also refer to anyapparatus housing, holding, or containing a methane-consumption systemsuch as microorganisms, fuel cells, or microturbines. In one embodiment,this apparatus comprises a holding tank containing methane-utilizingmicroorganisms and a microorganism growth-culture medium. In anotherembodiment, this apparatus comprises the materials housing and/orsupporting the operation of a reverse-flow reactor, an engine, a fuelcell, and/or a microturbine. In another embodiment, this means comprisesa temperature-controlled, stainless-steel cylindrical bioreactorapparatus containing, holding, or enclosing methanotrophic microorganismgrowth-culture medium and methane-utilizing microorganisms, into whichenclosure air, including ammonia and ruminant animal methane, is fed,conveyed, or directed, which subsequently allows microorganisms to growand reproduce utilizing ruminant animal methane as a source of carbonand/or energy for growth. In another embodiment, the growth of random,non-specified, genetically-engineered, pre-determined, and/ornon-pre-determined methane-utilizing microorganisms in such a bioreactormay be used to lower the concentration of ammonia in enclosure air. Inanother embodiment, means are provided to trap or capture dust and otherairborne matter in the enclosure air such that any or all of such matterdoes not actually contact a methane-consumption means, such asmethane-utilizing microorganisms or a methane-driven microturbine,reverse-flow reactor, or fuel cell. In this way, a mutual-exposure meansmay be used not only to carry out methane-driven processes, but also tolower the dust, ammonia, and/or airborne matter contents in enclosureair.

Several embodiments of the subject invention pertain to the utilizationof the enteric fermentation methane produced by ruminant animals for theproduction of methane-based goods. More particularly, some embodimentsof the present invention pertain to the process of utilizing ruminantanimal enteric fermentation methane emissions in which the methodcomprises: (a) providing one or more ruminant animals, (b) providingenteric fermentation-derived methane gas that has been emitted by theanimals, including air containing the methane, (c) providing means tocapture, consolidate, and/or direct the methane, including an enclosuremeans to enclose the animals, the air, and the methane contained in theair, and, preferentially, a ventilation means to direct the air, (d)providing a methane-consumption means which can use the methane as asource of carbon and/or energy for the induction of a methane-basedprocess and/or for the production of methane-based goods, and (e)contacting the methane with the methane-consumption means to cause themethane-consumption means to oxidize, consume, and/or otherwise utilizethe methane for the operation of a methane-based process or for theproduction of one or more methane-based products, includingmethane-utilizing microorganisms, heat, and/or electricity. Anotherembodiment of the invention pertains to the process wherein: a) one moreruminant animals are fully or partially enclosed by a well-knownenclosure means, such as a barn, and b) air contained in an ruminantanimal enclosure means, including the enteric fermentation methanecontained therein, is further directed and exposed to amethane-consumption system, whereby enteric fermentation methane is usedas a novel source of carbon and/or energy for the production of heat,electricity, or, as in one preferred embodiment, methane-utilizingmicroorganisms.

In one preferred embodiment, the method of the subject inventioninvolves contacting enteric fermentation methane contained withinenclosed barn air with a microbiological methane-consumption system,wherein enteric fermentation methane, methane-utilizing microorganisms,and a microorganism growth-culture medium are mutually-exposed, causingmethane-utilizing microorganisms to grow using enteric fermentationmethane as a source of carbon and/or energy.

FIG. 4 is a flow chart of a process carried out in accordance with theinvention. In the schematic, ruminant animal 114 is situated inenclosure means 115, whereby ruminant animal 114 is substantiallyenclosed, isolated, and contained by and in enclosure means 115. In onepreferred embodiment, enclosure means 115 includes a barn with foursidewalls and a roof

Enclosure means 115, in one embodiment, contains enclosure air 120.Enclosure means 115 is equipped with air inlet 116 and air outlet 117,through which air, gases, and other airborne materials are substantiallyconfined to enter and exit enclosure means 115, respectively. In onepreferred embodiment, air inlet 116 consists of a spatial opening, suchas a window, in a side wall of enclosure means 115, and air outlet 117consists of a spatial opening housing ventilation means 113, throughwhich air, gases, and other airborne material exit out of insideenclosure means 115. In one preferred embodiment, ventilation means 113consists of a well-known ventilation fan that is used to pull air intoenclosure means 115 through air inlet 116 and convey air out ofenclosure means 115 through air outlet 117.

Consolidation means 118, in one embodiment, is a duct that directsenclosure air 120 coming out of air outlet 117 in such a way that it canbe contacted with confined methane-utilizing microorganisms 121. In theembodiment depicted, mutual-exposure means 119 is a holding tankcontaining a methane-consumption means, embodied as methane-utilizingmicroorganisms 121, and microorganism growth-culture medium 122. In theembodiment depicted, methane-utilizing microorganisms 121 are present ingrowth-culture medium 122 at a concentration of 20 grams ofmicroorganisms per liter of medium, and consist of methane-utilizingmicroorganisms such as Methylococcus capsulatus that can be obtainedfrom any number of well known biological supply depots (including ChangBioscience, located at 125 Cambon Drive #6H, San Francisco, Calif.94132). Growth-culture medium 122, as herein embodied, is an aqueousmedium containing suitable ammonium, mineral salts, and other well-knowngrowth-culture components, which support the growth of methane-utilizingmicroorganisms 121.

The following is a description of one method by which to carry out aprocess in accordance with one embodiment of the invention. First,ruminant animal 114 is enclosed by enclosure means 115, and ruminantanimal emits methane gas into enclosure air 120 through processesassociated with enteric fermentation. Next, through the force ofventilation means 113, air is conveyed into enclosure means 115 throughair inlet 116, through enclosure means 115, and out of enclosure means115 through air outlet 117. Enclosure air 120 containing entericfermentation methane is next conveyed out of air outlet 117, throughconsolidation means 118 to be contacted with methane utilizingmicroorganisms 121 in mutual-exposure means 119 through the forcecreated by ventilation means 113. Inside mutual-exposure means 119,enteric fermentation methane contained within enclosure air 120 isexposed to methane-utilizing microorganisms 121 and growth-culturemedium 122, causing methane-utilizing microorganisms 121 to grow andreproduce using enteric fermentation methane as a source of carbonand/or energy. The process continues when, after a certain amount oftime (in this embodiment approximately 7 days) it is determined thatmethane-utilizing microorganisms 121 within mutual-exposure means 119are no longer growing at optimal rates, and the microorganism growthprocess is augmented by removing portions of growth-culture medium 122and methane-utilizing microorganisms 121 from mutual-exposure means 119and adding new portions of growth-culture medium 122 and/ormethane-utilizing microorganisms 121. In such a manner, entericfermentation methane is continually used as a source of carbon and/orenergy for the continuous growth and harvesting of methane-utilizingmicroorganisms. Finally, methane-utilizing microorganisms 121, havingbeen grown in mutual-exposure means 119 using enteric fermentationmethane as a source of carbon and/or energy, are removed frommutual-exposure means 119 and harvested as useful biomass. Such biomasscan be processed and sold as a range of useful biomass-based products.

In one preferred embodiment, as described earlier, ventilation means 113are employed to move 10 cubic feet of enclosure air 120 out of airoutlet 117 each minute, such that fresh air enters into enclosure means115 at the same rate, and enclosure air 120 is cooled by the air coolingmeans described earlier. As described, a dairy cow producesapproximately 150 kilograms of methane per year, which correlates to theproduction of approximately 0.4 liters per minute of entericfermentation methane. Thus, by enclosing ruminant animal 114 withenclosure means 115 and employing ventilation means 113, theconcentration of methane in enclosure air 120 conveyed intomutual-exposure means is at least 0.1% methane by volume, or 1000 partsper million. By decreasing or increasing ventilation rates, theconcentration of methane in enclosure air 120 increases or decreasesaccordingly. Methane-utilizing microorganisms are able to grow andreproduce using methane as a source of carbon and/or energy in anenvironment wherein the concentration of methane-in-air is at least 1.7parts per million. Thus, methane-utilizing microorganisms 121 areenabled to grow and reproduce using enteric fermentation methane as anovel source of energy in one preferred embodiment.

Several embodiments of the present invention pertain to the utilizationof enteric fermentation as a novel source of energy for the productionof methane-based goods in a confined methane-consumption apparatusexisting outside the digestive tract of a ruminant animal. There are anumber of potential methods that can be used to carry out a process inaccordance with embodiments of the invention. In particular, there are anumber of methods that can be utilized to capture enteric fermentationmethane with enclosure and ventilation means and mutually-expose entericfermentation methane and a methane-consumption means for the purpose ofcausing enteric fermentation methane to be utilized as a source ofcarbon and/or energy.

In some embodiments, such methods include, but are not limited to,providing methane-consumption means to convert enteric fermentationmethane into heat and/or electricity. In one embodiment, methane iscapable of being used at a methane-in-air volumetric concentration downto abut 0.1% methane-in-air, specifically by catalytic and thermalflow-reversal reactors. Thus, systems such as these could be used as ameans to utilize enteric fermentation as a viable, low-concentrationsource of energy in accordance with the invention. Specifically,microturbines, fuel cells, reverse-flow reactors and other means capableof utilizing methane at low concentrations can be used as amethane-consumption means in accordance with the invention, allowingenclosure air to be used in an unadulterated state as viable feedstockfuel. Gas concentrators that increase methane-in-air concentrations ofexhaust gas could also be employed to increase methane concentrations tolevels more suitable for use by a range of methane-consumption means.Thus, although one preferred embodiment details the use ofmethane-utilizing microorganism as a preferred methane-consumptionmeans, in another embodiment, any number of methane-consumption meansmay be employed in accordance with embodiments of the invention toconvert enteric fermentation methane into useful products such as heatand/or electricity.

In some embodiments, such methods also include the combined use ofnon-enteric fermentation methane and enteric fermentation methane in orby a methane-consumption means, such that enteric fermentation methanecan be partially used to drive one or more methane-consumption means,such as fuel cells, turbines, microturbines, methane-utilizingmicroorganisms, and other methane-based systems. Such alternativesources of supplemental methane might include: methane from agriculturalmanure digesters, agricultural manure holding structures, landfills,coal mines, wastewater treatment facilities, and/or natural gas.

In some embodiments, such methods further include the utilization of achemical-based methane-consumption means to use enteric fermentationmethane as a source of carbon and/or energy. Specifically, a number ofmethods are well known to convert methane into industrial feedstockproducts, such as methanol, through the mutual exposure of methane andvarious chemicals under a variety of conditions. Suitable chemicalprocessing methods of this nature could be applied to entericfermentation methane in accordance with the principles of the invention,especially through the combined use of enteric fermentation methane andalternative sources of methane, as enumerated above, to increase theyields, viability, and efficiency of the process.

In several embodiments, such methods also include usingmethane-utilizing microorganisms to simultaneously reduce both ammoniaand methane emissions from ruminant animal feedlots. In one preferredembodiment, enclosure air 120 will likely contain varying amounts ofammonia gas. It is well known that contacting ammonia gas with liquidwater changes ammonia gas into aqueous ammonium, as would occur inmutual-exposure means 119 of one preferred embodiment listed above whenenclosure gas 120 is contacted with growth-culture medium 122. It iswell known that methane-utilizing microorganisms utilize ammonium inwater as a source of nitrogen for growth. Thus, one embodiment of theinvention may include the use of unadulterated enteric fermentation tonot only produce methane-utilizing microorganisms, but to simultaneouslyreduce feedlot ammonia emissions as well.

In some embodiments, such methods also include using enclosure meansand/or methane-consumption means, as detailed above, to reduce dust orsuspended particles emissions associated with ruminant animals. In orderto increase the efficiency of a methane-driven system as detailed above,a filter may be used to prevent dust and/or other airborne particlesfrom entering into mutual exposure means 119. Thus, a process employedin accordance with the invention may be used to reduce entericfermentation methane emissions while simultaneously reducing emissionsof suspended particles typically associated with ruminant animals.

In some embodiments, such methods further include providing means toconvey enclosure air 120 from areas enclosed by enclosure means 115where enteric fermentation methane is known to accumulate, such as nearfeeding tracts, roof lines, or other potential methane accumulationareas. Such methods also include situating a means for mutual-exposurecontaining a methane-consumption means inside of an area enclosed anenclosure means, wherein means may or may not be provided tocontinuously or mechanically direct enclosure air to contact amethane-consumption system, but in either case causing entericfermentation to be utilized as a source of energy for the production ofmethane-based goods.

In one embodiment, enteric fermentation methane is used as a novelsource of energy for the production of methane-utilizing microorganismsin a confined growth-and-harvest apparatus existing outside of thedigestive tract of a ruminant animal. There are a number of potentialmethods that can be used to carry out a process in accordance with theinvention. In particular, there are a number of methods that can be usedto mutually-expose enteric fermentation methane, methane-utilizingmicroorganisms, and a microorganism growth-culture medium for thepurpose of causing methane-utilizing microorganisms to grow usingenteric fermentation methane as a source of carbon and/or energy.

In some embodiments, such methods include confining a ruminant animal toa site provided with means to funnel, convey, and/or direct entericfermentation methane into an apparatus whereby such enteric fermentationmethane is used to grow methane-utilizing microorganisms in a confinedapparatus, and whereby the means used to carry out this process areeither partially situated on a ruminant animal or not at all situated ona ruminant animal.

In some embodiments, such methods also include providing means to conveyenteric fermentation methane from a site where ruminant animals areknown to frequent, such as feeding or sleeping areas, to a means for themutual-exposure of enteric fermentation methane, methane-utilizingmicroorganisms, and a microorganism growth-culture medium, wherebymethane-utilizing microorganisms grow using enteric fermentation methaneas a source of carbon and/or energy in an apparatus existing outside ofthe digestive tract of a ruminant animal.

In some embodiments, such methods also include causing methane-utilizingmicroorganisms to grow by mutually-exposing enteric fermentationmethane, methane-utilizing microorganisms, and a microorganismgrowth-culture medium in a confined apparatus, wherein some or all ofthe methane-utilizing microorganisms are genetically-engineered.

In some embodiments, such methods also include growing methane-utilizingmicroorganisms using enteric fermentation methane as a source of carbonand/or energy for such growth, whereby the means used to carry out theprocess are powered by solar, wind, methane-based, or other suitableform of power different from the source of power—battery power—mentionedin the above detailed description.

There are also a number of methods in accordance with severalembodiments of the invention that can be used to mutually-expose entericfermentation methane, methane-utilizing microorganisms, and amicroorganism growth-culture medium for the purpose of causingmethane-consumption systems to operate using enteric fermentationmethane as a source of carbon and/or energy.

In some embodiments, such methods also include collecting, storing,and/or transporting ruminant animal methane (or gaseous emissions fromnon-animal sources) for later use in a process carried out in accordancewith the invention.

The following Example illustrates some embodiments of the presentinvention and is not intended in any way to limit the invention.Moreover, the methods described in the following example need not beperformed in the sequence presented.

Example 1

The following example describes the processing of methane emissions froma landfill site. One of skill in the art will understand that the methoddescribed herein can also be used for any site that produces methane,such as coal mines, wastewater treatment plants, manure digesters,agricultural digesters, compost heaps, or enclosed agriculturalfeedlots.

In one embodiment, a landfill site that produces methane emissions willbe identified. Landfill gas extraction wells and blowers are employed todraw landfill gas out of the landfill using equipment and technologythat is used by any landfill gas extraction or environmental servicesfirm, such as LFG Technologies of Fairport, N.Y., USA or SCS Engineersof Long Beach, Calif., USA. The methane content of the extractedlandfill gas can be monitored for the production of methane using anymethane detector commonly used by an environmental services firm. If themethane concentration is greater than about 1%, the landfill will bedeemed suitable for methane recovery and processing. In someembodiments, the methane concentration is between about 10% and 60%,more preferably between 40% and 50%. In other embodiments, methaneemissions comprise methane in a concentration in the range of about 0.1%to about 10%, in the range of about 10% to about 20%, or in the range ofabout 20% to about 40%, or greater than about 20%. Landfill sites (orother sites) having methane concentrations less than 1% and greater than60% may also be used in some embodiments of the invention.

After a suitable landfill site has been identified, the landfill gaswill be captured from the landfill using an air compressor, blower,vacuum, or other suitable capturing means. Impurities will then beremoved from the landfill gas. For example, non-methane organiccompounds can be removed by passing the landfill gas through activatedcarbon, leaving mostly methane and carbon dioxide as the main componentsof the landfill gas. Although impurities need not be removed in everyembodiment of the invention, the removal of impurities is advantageousin some embodiments. One advantage of removing impurities (such as watervapor, volatile organic compounds, particulate materials, and/or carbondioxide) is minimizing the possibility of hindering microorganism growthas microorganisms contact the landfill gas.

The landfill gas is optionally disinfected using UV light. In thoseembodiments in which impurities are removed, UV irradiation can be usedbefore, after or during the removal process. UV irradiation may also beused in embodiments that do not employ impurities removal. UV light isbelieved to disinfect the landfill gas by disrupting the nucleic acidstructures within microorganisms in the landfill gas, subsequentlyeliminating the capacity of these microorganisms to reproduce.Impurities removal and disinfection do not have to be employed, however,because methanotrophic microorganisms can withstand a range ofimpurities.

The landfill gas (which in a preferred embodiment is purified anddisinfected) as well as air or oxygen (which in one embodiment ispurified and/or disinfected) will be fed into a self-contained enclosureusing an air compressor, air blower, or similar means. Theself-contained enclosure is preferably a bioreactor that contains atleast one species of methanotrophic microorganisms and growth medium.The bioreactor is preferably sized to accommodate the flow rate oflandfill gas to be treated. For example, a bioreactor treating 1000cubic feet per minute of landfill gas should be approximately twice aslarge in volume as a bioreactor treating 500 cubic feet per minute oflandfill gas. Preferably, a bioreactor treating 1000 cubic per minute oflandfill gas will contain about 100,000-800,000 liters of growth mediumcontaining suspended methanotrophic microorganisms. Growth medium can bea liquid, semi-liquid, or solid substrate. For example, the growthmedium may be water containing growth nutrients such as nitrogen andtrace minerals, in which microorganisms are suspended.

In one embodiment, the growth medium can be tailored to meet thespecification of the end-product of microorganism growth. If thebioreactor is being used to create soluble methane monooxygenase, forexample, it will be preferable to keep the copper concentration in thegrowth medium sufficiently low, for example, below about 5×10⁻⁹ M, whichmay be achieved through continuous monitoring of the growth medium andcalculated metering of copper into the growth medium.

The growth medium solution may consist of water filled with a range ofmineral salts. For example, each liter of growth medium may be comprisedof 1 g KH₂PO₄, 1 g K₂HPO₄, 1 g KNO₃, 1 g NaCl, 0.2 g MgSO₄, 26 mgCaCl₂*2H₂O, 5.2 mg EDTA Na₄(H₂O)₂, 1.5 mg FeCl₂*4H₂O, 0.12 mgCoCl₂*6H₂O, 0.1 mg MnCl₂*2H₂O, 0.07 mg ZnCl₂, 0.06 mg H₃BO₃, 0.025 mgNiCl₂*6H₂O, 0.025 mg NaMoO₄*2H₂O, 0.015 mg CuCl₂*2H₂O, or a combinationthereof. In another embodiment, the growth medium comprises solid and/orliquid media. In yet another embodiment, the growth medium comprisesagar.

Methanotrophic microorganisms may be present in the bioreactor in anyconcentration. Preferably, in one embodiment, there are about 1 to 100grams of microorganisms per liter of water (or other aqueous solution)in the bioreactor, preferably about 10-50 grams per liter, morepreferably about 40-50 grams per liter, over the course of treatment.The methanotrophic microorganisms are exposed to the methane withinlandfill gas for about 1-200 hours, preferably about 24-96 hours,whereupon a portion of the microorganisms within the bioreactor,preferably about 10-50%, are removed and replaced with fresh growthmedia or growth media containing a low concentration of microorganisms,in order to allow more methanotrophic microorganisms to grow in thebioreactor and continue to treat the methane within the landfill gas athigh rates.

The microorganisms that are removed from the bioreactor are processedfurther according to the specification of the end-product ofmicroorganism growth. For example, if the microorganism biomass is to beused directly as a protein source, the suspended biomass may bedewatered in a belt filter press, bag filter, spray drier, and/orcentrifuge, all of which may be used to reduce the water content of thebiomass, preferably below about 10-20% total biomass weight. If themicroorganism biomass is to be used to generate a polymer such as PHB,the microorganisms may be exposed to a bioreactor receiving a continuoussupply of landfill gas and air or oxygen, wherein the growth medium isdeprived of a specific essential nutrient, such as nitrogen, in order tocause the microorganisms to synthesize intracellular PHB. After a periodof about 1-3 days, some portion of the bioreactor may then be removed inorder to harvest the products of bioreactor growth, in this case PHB.PHB may be harvested through a variety of well known cell extraction andpolymer purification techniques. Dewatering methods may include, but arenot limited to, the use of centrifuges, spray driers, or belt filterpresses. Cell lysis and cell parts separation methods may include, butare not limited to, the use of hot chloroform, sodium hydroxide, cellfreezing, sonication, and homogenization. For homogenization, thepressure drop is preferably between about 5000 and 10,000 bar to effectsufficient cellular lysis. For the use of sodium hydroxide, theconcentration of sodium hydroxide is preferably raised to approximately2 M. Isolated, dried, and harvested microorganism product, such asbiomass, polymer, or enzyme, may be used or sold for use.

While the above description of preferred systems and methods of carryingout processes in accordance with embodiments of invention contains manyspecificities, these should not be construed as limitations on the scopeof the invention. As stated, there are a number of ways to carry out aprocess in accordance with invention. Accordingly, the scope of theinvention should be determined not by the preferred systems and methodsdescribed, but by the appended claims and their legal equivalents.

1-35. (canceled)
 36. A method of directing a plurality of microorganismsto produce a single type of harvestable polymer, the method comprising:providing a gaseous emission, wherein said gaseous emission comprisesmethane, one or more non-methane organic compounds, and a plurality ofmethanotrophic microorganisms that metabolize said methane and saidnon-methane organic compounds; providing a microorganism growth-culturemedium, wherein said medium comprises one or more growth-culturecompounds; exposing said gaseous emission to said growth-culture mediumover a course of time, wherein the concentration of at least one of themethane and the one or more non-methane organic compounds within saidemission is variable, wherein said methanotrophic microorganisms use atleast a portion of said methane as a source of carbon or energy toinoculate said medium to create a naturally-equilibrating consortium;and varying the concentration of said one or more growth-culturecompounds to cause substantially all of said methanotrophicmicroorganisms within said medium to generate a single type of polymer,thereby directing a plurality of diverse microorganisms to produce asingle type of harvestable polymer.
 37. The method of claim 36, whereinsaid single type of polymer consists essentially of polymers that arestructurally similar.
 38. The method of claim 36, wherein said singletype of polymer consists essentially of polymers that are functionallyequivalent.
 39. The method of claim 36, further comprising addingadditional methanotrophic microorganisms to said medium.
 40. The methodof claim 36, wherein said plurality of methanotrophic microorganismscomprise at least two different species of methanotrophicmicroorganisms.
 41. The method of claim 36, wherein said polymer isselected from the group consisting of one or more of the following:polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB),polyhydroxybutyrate-valerate (PHB/V), methane monooxygenase, and singlecell protein.
 42. The method of claim 36, wherein the step of varyingthe concentration of said one or more growth-culture compounds comprisesreducing or eliminating copper.
 43. The method of claim 36, wherein saidone or more growth-culture compounds are selected from the groupconsisting of one or more of the following: nitrogen, copper, magnesium,phosphorus, oxygen, carbon, potassium, and iron.
 44. The method of claim36, further comprising removing impurities from said gaseous emission.45. The method of claim 36, wherein said gaseous emission comprisesmethane at a concentration in the range of about 0.1% to about 60%. 46.The method of claim 36, wherein said gaseous emission is generated by asystem selected from the group consisting of one or more of thefollowing: coal mine, wastewater treatment operation, agriculturaldigester, enclosed feedlot, petroleum transport system, petroleumrecovery system, landfill, ruminant animal, and compost facility. 47.The method of claim 36, wherein said methanotrophic microorganismscomprise at least one of a naturally-occurring or genetically-modifiedmicroorganism that uses methane as a source of carbon or energy forgrowth or reproduction.
 48. The method of claim 36, wherein said one ormore non-methane organic compounds are partially or fully metabolized byone or more said methanotrophic microorganisms.
 49. The method of claim36, wherein said one or more non-methane organic compounds are partiallyor fully oxidized by one or more said methanotrophic microorganisms. 50.A system for directing a plurality of microorganisms to produce a singletype of harvestable polymer, comprising: a source of gaseous emissions,wherein said gaseous emissions comprise methane, at least onenon-methane organic compound that influences the metabolism ofmethanotrophic microorganisms, and methanotrophic microorganisms capableof metabolizing said methane and said non-methane organic compound; agrowth-culture medium, comprising one or more growth-culture compounds;a bioreactor that encloses or contains said emissions and said medium; aconveyer that conveys said gaseous emissions into said bioreactor andvaries the concentration of at least one of said methane or saidnon-methane compound; wherein said methanotrophic microorganisms use aportion of said methane to inoculate said medium to generate anaturally-equilibrating consortium; and wherein said methanotrophicmicroorganisms generate a single type of polymer after said one or moregrowth culture compounds are altered.
 51. The system of claim 50,wherein said single type of polymer consists essentially of polymersthat are structurally similar.
 52. The system of claim 50, wherein saidsingle type of polymer consists essentially of polymers that arefunctionally equivalent.
 53. The system of claim 50, further comprisingan additional source methanotrophic microorganisms that is independentof said gaseous emission.
 54. The system of claim 50, wherein said oneor more growth-culture compounds are selected from the group consistingof one or more of the following: nitrogen, copper, magnesium,phosphorus, oxygen, carbon, potassium, and iron.
 55. The system of claim50, wherein said gaseous emission comprises methane at a concentrationin the range of about 0.1% to about 60%.
 56. The system of claim 50,wherein said gaseous emission is generated by a system selected from thegroup consisting of one or more of the following: coal mine, wastewatertreatment operation, agricultural digester, enclosed feedlot, petroleumtransport system, petroleum recovery system, landfill, ruminant animal,and compost facility.
 57. The system of claim 50, wherein saidmethanotrophic microorganisms comprise at least one of anaturally-occurring or genetically-modified microorganism that usemethane as a source of carbon or energy for growth or reproduction. 58.The system of claim 50, wherein said plurality of methanotrophicmicroorganisms comprise at least two different species of methanotrophicmicroorganisms.